Protective device.



Patented Oct. 17,1916.

Invefitor 9 1% torneg annua v all IE Charies ste'nrneti tart a CHARLES P. STEINMETZ, O1 SCHENECTADY, NEW" YORK, ASSIGNOR TO GENERAL ELECTRIC GOIVIPANY, A COIRPORATION OF NEW YORK.

PROTECTIVE DEVICE.

Application filed April 21, 1916.

To all whom it may concern:

Be it known that 1, CHARLES P. STEIN- METZ, a citizen of the United States, residing at Schenectady, county of Schenectady,

State of New York, have invented certain new and useful Improvements in Protective Devices, of which the following is a specification.

My invention relates to protective deo vices and more particularly to that class of protective devices known as lightning arresters.

In lightning arresters in which a discharge takes place across a spark gap between two electrodes, it has been found that when an accident occurs in which the low voltage circuit which is protected by lightning arresters becomes crossed with a high voltage power circuit or the like, the dis charge across the spark gap of the arrester becomes practically continuous. Silch a con tinuous discharge generates an excessive heating which if allowed to continue eventually destroys the arr-ester.

The object of my invention is to provide a protective device of the lightning arrester type with a novel and improved device for, short circuiting the arrester when the heat generated by the discharge of the 80 spark gap becomes excessive.

The novel features which I believe to be characteristic of my invention will be defined in the claims appended hereto; the features of construction and mode of operation will be understood by reference to the fol- -lowing description taken in connection with the accompanying drawing, in which the figure of the drawing shows a side elevation, partly in section, of a lightning arrcster embodying the novel features of my invention.

In the figure, I have shown my novel short-circuiting device applied, by way of example, to a lightning arrestcr in which the spark gap between the electrodes takes place in an inert atmosphere. The lightning ar'rester unit itself forms no part of my invention, this arr-ester unit being covered in U. S. Patent 1,176,544, issued to George F. Gray. A brief description of the arrester will, therefore, be suiiicient.

'lhis'protectivc device comprises a lightning arrester unit 1 which comprises a hollow: or tubular electrode 2 preferably of metal which contains an inert atmosphere 6 and a cooperating electrode 3 which l have Specification of Letters Extent.

Patented Oct. 17, 1916.

Serial No. 92,736.

shown as a disk, preferably of non-arcing metal, mounted within the tubular electrode 2 and separated therefrom to form an annu lar spark gap A rod 5 is secured to the electrode 3 and extends outside the electrode 2. The electrode 2 is closed at one end by a suitable air-tight seal 6 and a porcelain plug 7 through which rod 5 extends. Around the inside of the electrode 2, adjacent the spark gap a, is placed a sleeve 8 of preferably non-arcing metal. The hollow electrode 2 has at its end opposite the seal, a depression containing a fusible material or solder 9. A small opening is made through the material 9 in alinement with a small perforation 10 in the end of the tube by means of which the hollow electrode 2 is evacuated or supplied with an inert gas. After evacuation, the material 9 is melted and closes the perforator 10 to maintain the hollow electrode gas-tight. Directly beneath the depressed end of the electrode and within the electrode is mounted a dia phragm 11 having protuberances 12 with openings at their apices and forming between the protuberances a pocket which is provided to catch and hold any fusible material which may get through the perforation 10 and prevent it from bridging the spark gap 4: between the electrodes. The two cooperating electrodes 2 and 3, constructed as described, form a unit construction.

An insulating support 13 is provided upon which is mounted a line connecting terminal adapted to be connected to the line or conductor 14 to be protected, and a ground connecting terminal adapted to be connected to ground. The line connecting terminal, I have shown as a spring clip member 15 for holding the hollow electrode 2 and the ground connecting terminal as a spring member 16 bent upon itself, one portion of which is perforated to hold the rod 5 which isconnected to the disk electrode 3. The protective unit 1 is thereby adapted to be removably positioned betweenjthe two teri'ninals 15 and 16 to connect, for instance, electrode 2 to the line to be protected as comluctor 14 and electrode 3 to ground. For protecting this arr-ester from heavy and continuous discharge across the spark gap 4 between electrodes 2, and 3', I mount upon the insulating support 18 my novel shortcircuiting device comprising -'a metal spring conducting memberll' yieldingly mounted which the pellet of 4 mounted.

trode through the spri on the terminal post 18 and thereby electrically connected to the disk electrode 3. it will be understood that I may secure the spring member 17 in like manner to terminal post 19, if I so desire. In the construction shown, I secure the spring member 17 to the terminal post 18 in such a way as to biased toward engagementwith he hol low electrode 2, the member 17 extending along the electrode to a point approximately adjacent the spoil gap l. 'lhemezm her 17 is shaped to provide an engaging or o'llset portion 20 which is nearer the elec trode 2 than any other portion so that the spring member always engages the electrode 2 at the portion 20. The spring member 17 and its engaging portion 20 held away from the electrode 2 in a non-short-circuitieg position, by means of a piece or pellet of a heat-responsive or fusible material 21 havii a high melting point. This pellet is held in engagement with the hollow electrode 2 and in heat conducting or thermal relation therewith by the bias of the spring member 1'? and is insulated the mem ber 17 by a disk of insulating material secured on the end of member 17 upon fusible material 21 is Under normal conditions the short-circuit- .ing device is inoperative the heat generated by intermittent discharges of the arco. to

discharge of the a r instan a cross of the ligh arr r circa a power line, the heat generated is Show to cause the fusible material 21 to melt and the biased spring men? er ll then moved toward the hollow electrode 2 until its engag inc; portion 20 touches the electrode Whereupon the arrester is short cireuited. and the heavy currents are coodncted "from the elecmember I? to eiitiiig tits destruction of ground, time prev the arrester.

v invention may be embodied. in other fora than that shown and described and i thcrel'ore rlo not Wisliv be restricted to the precise construction shown but intend to cover by the appended claims all chan es and modifications Within the spirit and. :cope of my invention.

W hat I claim as new and desire to secure Ly Letters Patent f the. United State's. is,--

l. A protective device comprising a hollow electrode and a cooperating lectrode mounted Within said hollow electrode and separated therefrom by a spark gap, means for Sl1()Il)C1lCu1t1ng sald arrcster comprising a conducting member electrically connected tosaid cooperating electrode and normally biased to engage said holloW- electrode, and; heat-responslve means held in heat-conduct mg relation with said hollow electrode by the bio means (filmed by said eoin'lnc short-clreuitirig position insulating means between. said heat-responsive means and said conducting member said. heatresponsive means adapted to melt by the heat generated.

of said spark member to move insulated their 1 low elect-rode in the p: ap to normally in d 1" said spring mom low electrode, means being aciipted to melt Generated by the o and allow leg member J, i tne engagiog po and shortto said 3 with siege hollow ele =ectrodcmount remova oly positto connect said electrodes ,g rouncl and T i, one of said terminals .lIlCa" elite said hollow electrode to a pity to said spar gap, a pellet oi teriai carried b" said 5; n

insulated ther mm, said spring biased to hold said pellet in therma eligagement with said hollow electrode 4 point in. proximity to said. spring member having portie" adapted to er e said. hollow o. short-circuit said air-roster upozc of said fusible material.

The coirilsination with a li comprising tubular met trode containing an inert atmosphere and cooperating; disk electrode mounted ithin said tubular electrode and separated thereing device for said arrester comprising; a.

resiliently nionnted conducting member in electricalcomiection with said disk electrode and biased to engage said tubular electrode, a pellet of fusible material. in thermal engagemcnt with said tubular electrode and ,risirw a hollow from to form a spark or she-:rtcircuih heat of excessive discharge across said spark gap to allow said conducting member to engage said tubular electrode and thereby short-circuit said arrester.

5. The combination with a lightning arrester comprising a tubular metallic electrode containing an inert atmosphere and a cooperating disk electrode mounted within said tubular electrode and separated therefrom to form a spark gap, of means for short-circuiting said arrester upon excessive discharge across said spark gap comprising a short-cirouiting member yieldingly mounted outside said tubular electrode and in electrical connection with said disk electrode, said short-circuiting member being biased to engage said tubular electrode, a pellet of fusible material secured to said short-circuiting member and in thermal relation with said tubular electrode adapted when melted to allow short-circuiting member to engage said tubular electrode to short-circuit said arrester.

6. ha protective device, the combination with a protective unit comprising two electrodes normally separated by a spark gap, one of said electrodesbeing a hollow member, the other of said electrodes being a disk member mounted within said hollow memher, an insulating support, a line connecting terminal mounted on said support, a ground connecting terminal mounted on said support, said protective unitbeing removably positioned between said terminals to connect said electrodes between line and ground, and a spring'conducting member secured to one of said terminals and having a portion thereof adapted to engage said hollow electrode, a pellet of high melting point material in thermal engagement with said hollow electrode and normally preventing the engage ment therewith of said spring member, and means for insulating said pellet from said spring member, the melting'of said pellet causing the engaging portion of said spring member to engage said hollow electrode, and thereby short-circuit said arrester.

In witness whereof, I have hereunto set my hand this 20th day of April,1916.

CHARLES RSTEINMETZ. 

